I just picked up a posi disc rear out of an 86 tran-am. It is my understanding that all third-gens came with a 10 bolt rear. Is that 10 bolts that bolt the cover on? The rear-end I got has only 9. I'm confused. Please help.

 

You have a Borg Warner 9 bolt. It's stronger than a 10 bolt but parts are expensive and hard to find if you break anything. Nothing internal is exchangable with a 10 bolt. If it has a high gear. ie. 2.77 then you'll have to find a 9 bolt series 3 carrier to go to 3.27, 3.42, 3.70 gears.

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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

Best ET on a time slip: 11.242 altitude corrected to 10.69
Best MPH on a time slip: 121.52 altitude corrected to 127.76
Altitude corrected rear wheel HP based on power to weight ratio: 504.5
Best 60 foot: 1.546

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

Thanks man.

 

Now im stuck. Summit and Jegs dont sell gears for it. Where can I find a set?

 

Australia. That's where the diff was made.